Major Reduction of Wolves May Increase Prey Over Short Term;More Scientific Management Approach Needed

JUNEAU -- Wildlife managers in Alaska may be able to temporarily increase populations of moose and caribou for hunters by killing off a large percentage of wolves in designated areas over a span of several years, according to a new report* from a committee of the National Research Council. But shortcomings in the design of past predator control programs make it impossible to determine whether wolf or bear reduction programs are effective in the long term, the report says. Previous programs have not adequately considered the importance of habitat and weather changes, nor have they included the analyses necessary to determine whether the programs helped hunters or benefited the state's economy.

The Research Council was asked by the state of Alaska to examine the scientific and economic bases of its predator management programs, and to identify gaps that need to be filled to improve scientific understanding of the ways wolves, bears, and their prey interact."Except in cases where predator reduction has been substantial and sustained, it is difficult to determine whether most predator control experiments in Alaska have achieved their ultimate goal of improving hunting," said committee chair Gordon Orians, professor emeritus of zoology, University of Washington, Seattle. "By improving the design and monitoring of its predator control efforts, including both biological and sociological components, the state can close some of the gaps in understanding and help assure the public that it has considered all of the relevant information and interpreted it appropriately."

Wildlife management in Alaska includes any action designed to alter populations, such as killing, relocating, or sterilizing wolves, or hunting bears. Alaska has a long history of predator management, but it has not conducted wolf or bear reduction programs since late 1994, when Governor Tony Knowles suspended a wolf-trapping program designed to increase the number of moose and caribou available for hunting. Hunting has long been a part of Alaska's culture, both for subsistence and for recreation, and contributes to the state's economy. And though Alaska's predator control and management programs include bears, wolf reduction programs are the most controversial.

Under certain conditions, wolves and bears naturally limit moose and caribou populations. Reducing wolf numbers dramatically -- by as much as 40 percent or more for at least four years -- has been shown to increase prey over the short term. However, the methods that have been used in the past to achieve such reductions, including aerial-assisted hunting and poisoning, are no longer acceptable in Alaska, where voters approved a ban on same-day aerial hunting last year. And there are still too few data to assess the effectiveness of non-lethal methods, such as sterilization or feeding programs to divert predators from prey, the report says.

Limited Data

Despite considerable public investment in planning, designing, and implementing several predator control efforts in recent decades, they have not been designed and monitored to measure whether their goals were in fact achieved, the report says. Of the 11 predator-reduction programs in Alaska and Canada that were examined by the committee, only two measured whether hunting success improved after the predator population was reduced. In just five of the 11 cases did managers attempt to measure whether the population density of moose and caribou increased.

In many cases, the committee noted, action to reduce the number of wolves was accompanied by other changes such as reduction or elimination of hunting, which made it impossible to determine which factors caused changes to the moose and caribou populations. Further, many predator control experiments were initiated with inadequate consideration for whether the habitat could support increased moose and caribou numbers. And data are generally sparse on the density of bear populations in management areas, even though bears are believed to kill more moose calves each year than do wolves.

In only three cases, two of which were conducted in Canada, were enough data collected to determine whether wolf and bear reductions caused an increase in adult populations of moose and caribou. Although predator management may have achieved its goals more often than this, there is no scientific justification for the claim that it has. The Alaska Department of Fish and Game has rarely been given the resources it needed to use proper experimental designs and to monitor adequately the results of their management actions, the report notes.

Improved Methods, Better Understanding

Wildlife policy is most effective when it combines biologically sound management goals with research goals so that it is possible to determine whether certain interventions actually led to the desired results, the report says. It presents a set of guidelines for Alaskan officials to follow when considering a predator control plan.

Officials first should identify the reason or reasons for wanting to increase prey populations, such as a biological emergency, a need to improve recreational or subsistence hunting, or the desire for more wildlife for viewing and tourism. Once this is done, managers should determine how much of an increase in the prey population is needed, and analyze the full costs and benefits of meeting that goal. If the benefits appear to outweigh the costs, managers should conduct ecological investigations to assess the likelihood that predator control would achieve the intended objective.

Finally, if predator control is judged to be an appropriate way to meet a significant demand for prey, managers should explore a series of options for reaching their goals, including changes to the habitat through controlled burning or other means; experimenting with non-lethal methods like diversionary feeding, sterilization, and relocation; and selectively removing individual bears or wolf packs. Management interventions should include monitoring the long-term impacts of the action.

Economic Costs

Discussions of the economic effects of predator control usually focus on the financial implications of changes in employment or expenditures, but these measures alone do not provide a complete picture, the report says. Because people value wildlife in different ways, the economic benefits and costs of predator control include more than the value of the meat or the amount of income derived from hunting; they include broader considerations such as what people are willing to give up to gain some benefit, or how much people would be willing to pay to preserve a benefit they do not directly use.

Benefit-cost analyses of wildlife management actions should address at least three categories: biological relationships among prey, predators, and their environment; changes in how people hunt; and consideration of the different ways in which people value Alaskan wildlife. Past economic studies of predator control have not sufficiently addressed costs and benefits for all groups of people affected by Alaskan wildlife management actions, the report says. Because few data have been gathered on the full economic implications of predator control it is currently impossible to assess whether such control efforts are a net benefit to Alaska today.

Although the debate over predator control in Alaska has become increasingly polarized in recent years, the committee stressed that there is potential for agreement among the state's diverse constituencies if officials develop procedures that allow the public to be substantively involved in all aspects of the policy and regulatory process. Alaska should establish a formal conflict-resolution process for wildlife management decisions, and should partly decentralize decision-making by having substantive input from local parties and other interests. Where management decisions affect rural and indigenous groups, officials should develop appropriate ways of co-managing resources.

A committee roster follows. The report was sponsored by the state of Alaska. The National Research Council is the principal operating arm of the National Academies of Sciences and Engineering. It is a private, non-profit institution that provides advice on science and technology under a congressional charter.

* Copies ofWolves, Bears, and Their Prey in Alaska: Biological and Social Challenges in Wildlife Management are available from the National Academy Press at the mailing address in the letterhead; tel. (202) 334-3313 or 1-800-624-6242. The cost of the report is $37.00 (prepaid) plus shipping charges of $4.00 for the first copy and $.50 for each additional copy. Reporters may obtain copies from the Office of News and Public Information at the letterhead address (contacts listed above).

NATIONAL RESEARCH COUNCILCommission on Life Sciences

Committee on Management of Wolf and Bear Populations in Alaska

Gordon H. Orians*(chair)Professor Emeritus of ZoologyDepartment of ZoologyUniversity of WashingtonSeattle